Backlash take-up for gun elevating mechanism



Feb. 24, 1948.

G. I. C HlNN BACK-LSH lTAI'IE--UI FOR GUN ELEVATING MECHANISM lFiled Jan. 19, 1944 Patented Feb. 24,,'1948 Y assvs AcKLAsH TAKE-nr Fon een .mamme MEcHANrsM lGeorge '1. IChinn, Detroit, Mich. .Application January 19,1944, Senial INo. (Cl. B-T) (Granted :under the 'act of March 3, 1883@3 `:amended April 3l), 1928; 370 0. G. 757) '6 Claims.

*The 'invention Yiescriloed herein may be manw facturen and used by or yfor 'the Government zvfor governmental Dur-poses, Without the payment me Aoff any royalty thereon. l

'The `present invention pertains to fa `novel tievice Afor taking `'up the gear backlash "in guns which are balanced about the trunrions for the purpose of operation 'with a. y'gyro -s'tabilizer.`

coni-bat tanks `a lgS'r-o stabilizer is usel fior maintaining thn the target during motion ofthe Velicle. 'No'backl'ash 'take-up is require when the `Elin is so used. However, 'when the vehicle is not in motion and the VLg'uni-s employed asastationary 'eld piece, the elevationof the sun isemanua'ily conti-choo and Asome ta'cklash tatto up meansiis necessary. `"Tlf-ie"olojeetlof the rprescrit invention is to use a `portion ofthe gym stabilizer system, 'is otherwise inactive `at this time, for taking 'up tthe backlash.

i "Ihefg'yrostabilizersystem-includes a hydraulic cylinder Witha 4piston Afor effecting the elevation o'f 'thefvgun The gyroscope is acti-veen a toeter valve for admittingpressure nuicl =to-onesie or the 'dt-her ofthejp'iston,` Each Valve stem of xthe teet'er val-ve .is actuated by a coil, Vand the two 1 coils are `energizetl Vvaryin'gly :from the gyroscope mechanism.

"The "invention described herein comes :into use only when the gyroscopic system is not in use. The inventioneprovides a 'separate circuit ferienergizing only vlone of Athe coils in such a manner that thelpr'essure fllidis admitted to the fcylirrer on that lside foi the piston which v'exerts a down ward force aon the fbreech end 'o'f the "gun *the noln'tbeyoni 'the horizontal pivotal mounting.

I liis 'fooe 'is comparableto' the fdownward 'fierce 'which wvoibe prouce `=by 'counterweigfhtusee for the *purpose *di making the gun Eloreeels-heavy y*illustrative embodiment fof the invention 4is tlisclo'seciin 'the folowing description and in the accompanying .rawings in 'which the 'si-nele nre 'is `a schematic sectional `View foi 4fthe lampara tus'cornline'witna wiringfdiagram. The 'conventional fgun gyro-'stabilizer Ysystem will irst'fbe `descriloel. The fgun is mounten :on trunn'ions'?. ibove orloelow the gunis a'pivotgrounded at i3. wire l-U contains .aa master 'switch fit between "the -source ianti the branch 111.

fiston 4 lwith =a"ro 5 lpvota'lly lconnected to the igun Tat 'aip'oint f6 behind the trunnions.

"Phe Teailn 'Wire ID from fa suitall-e gnounile source of potential "brancheol "at 5i l to contain niidfptmipmtor "-I2 'for driving lthe two fluid pumps Acomprising ll `gears S335, F36, and f3?, anl branch fifi finally grounded `at i3; Another branch ill containsa gyra motor'- fl 5 an iis #also is openen Wier While ythe Between the branches ill ana I4 is a 4gyro circuit JW nsete lfin a. `-ooniflrlufaiton 'IU' fof fthe line il! ccnneete at 'it to the ygfromsidecl side ynl? brenda im. The exten-sion 'lll' contains n pilot iight itil".

To tl'ie extension 111D' is connected la resistor "Z0, with a 'switch i2! interposed. Another resistor 22 extencs Vfrom the point fIB to 'a 4point .23 between the resistor fanti the' switch '23. Two lspaced ksets 24 an f2'5 fof -contactm' flaes known as la silverstat are provided. *,IIhese are interconnected -at one end by aoonluctr 16 and arefnormally separate at 'their 'remaining ends vBetween fthe sets is actuator 2B adalited jtoloring into mutual engagement a varying number of blades at fone or the other stile jo' the actuator. `'-Ilce actuator is Jopera'tefl ifrom `a 'g'yrosc'ope` system l(not showni) m'uY-i'te on the vehicle. adjustable contact 2'9 on the resistor Q2 iis joined 'lby a conductor yt!! to the nonluctor 26 fait the space between the fs'ets 2l Iamd 525.

"The hylralc infill-ities a pump body "31 having twoparalll main passages f32 and 3'3 dis- `posed Witt-xine reservoir 33. Fluidis drawn from the reservoir anti tlischarged through :the lpassages `by VJtwo ipumpscorrusrising gears 35 vand 36 an *317. passages?! l'and V$3 are connecte at Jiawpnosite sitios foi the 'piston '11, 'Beyond their connections to the lines 1B and k319, the `passages 32 'are orme' with valve seats 3'2 and 33' ycom inuricatin'g freely with *the reservoir 34. V(3o-operating with e'the valve :seats is a toeter -valve 'comprsing'fa magnetic W3 p'ivfotaily mounted 'intermeiate its on 'the fulcrum 43', anti 'having seating eValve stems .f5-2 @an 33B extend ling trom the'opposite end -o'f 'the bar to the valve seats. tBy tilting fo *the "bar 43, L'one vvalve other "is correspondifn'g'ly The magnetic toeter im dass operateo "by eens dii can?! vk#il upon Icores 4'4 and d'5 respectively loca'teil salacerit `opposite 1ends of lthe 'fbar 43 each fco iriaving one fenii :connected *to 'a dif'- iererrt .fend of conuctor 1li-foy a conductor Wl 'or dile. The #remaining ends -o'f the coils Vfare "gloune `at i8. Ar0tf1n :the ocre M :is a bul-ler cell i9 fjinefby a .coriutor "50 to an yadjllstalle contact 'el cn the resistor 2l). YThe'conductor 50 'contains La 'Ys-Witch 152 which fis automatically close on tthe recoil fo' the gun. The fswitch 52 is mounted :upon a tstationarlyepart :of -th'e gun and normali-y lhl "ley `engagement iwith blades, and the relative resistance of the coils,A

46 and 41. With the switches I6 and I1 closed so that current flows in the system, the coll carvrying the larger current will move the corre-y sponding valve stem 32a or 33a towards its seat to reduce the aperture connecting the corre-v sponding passage and its by-pass. Thus,` the pump 35, 36, 31 will force fluid to one side of the yus piston 4, while the other side willy be opened l through the unobstructed by-pass to the reservoir 34. l

On the recoil of the gun, the switch 52 closes and energzes the coil 49. This closes the valve seat 33' so that uid is delivered beneath the piston 4 in the cylinder 3 t0 cushion the recoil.

As is 'conventional with guns of the typeprovided with a gyro stabilizer, vmanually actuated mechanical means is provided for moving the gun in elevation when the gyro stabilizer is not in use. This means is shown in the drawings as comprising an arcuate rack 85 mounted vertically on the gun I and a crank operatedigear train 83 having a pinion 84 for engaging-theY rack 85. As also is conventional with guns of this type, -the gear train is adapted to be disengaged from the rack 85 when the gyro stabilizerA is in use. As is well known, the gyro stabilizer and themanually actuated elevating means are not `used simultaneously. j

Conventional mechanical elevating systems, as is also well known, inherently have an appreciableamount of backlash, i. e., a play or moveical elevating mechanism. Movement of the gun by reason of this force is prevented by the irreversible functioning of the elevating gearing 83. However, this force or downward fluid pressure on the piston 4 is readily overcome by manual operation of the mechanical elevating l.mechanism in obtaining depression of the muzzle of gun I, the uid in cylinder 3 above the piston 4 and in line 39 then being escapable through the restricted aperture from passage 32 to the reser- 'V voir. 34. i

An oppositely acting or interlocking switch 62 maybe inserted in the conductor 41a between the blades 24 and the conductor 6U( to cut out the blades when the backlash take-up system is to be energized. However, the switch 62 is not always essential since suicient current to energize z the coil 41 will remain even if current flows elsement in the connected parts resulting from loosey ness, which is particularly disadvantageous when the gun is substantially balanced at the trunnions as is the usual gyro stabilized gun. In accordance with the present invention, the gyro stabilizer system is modified to permit it to be utilized during manual operation of the mechanical elevating means, when otherwise it would not be in use., to take up the backlash in the gearing of the mechanical elevating means. The modification, a description of which follows, is denoted by the solid lines of the wiring. diagram.

Referring to the drawings, a-conductor 60 is connected to the extension I6 and-` the conductor 41a through a resistor 64 and vrswitch 6I. When the mechanical elevating system is brought into use, the switch I1 or switch 2I, or both, are opened automatically or manually to disconnect the gyro control circuit. The switchV 6I, which remains open when the gyro stabilizer is used, is closed when the mechanical elevating. system is brought into use. Switch I6 remains closed during bothmoperations. Itthus will be seen that during-theluse of the mechanical elevating system, the iiuid pump motor I2 which drives-the fluid pump is energized, and bythe closing of switch 6I there is also energized the coil 41 which actuates the teeter valve stem 32a, causing the latter to move towards valve seat 32 thereby relaively restricting the aperture, leading to passage 32 and causing downward fluid pressure to be exerted on the piston 4.v The resulting downward pressure or biasing force exerted upon the gun bythe pressure applied tothe top of the piston 4 takes up all backlash present inthe mechanwhere. The voltage on the coil 41 is controlled by a dropping resistor 64 in the conductor 60. The energized coil 41 thus controlled causes relative restriction to a degree of the aperture at the valve seat 32 and corresponding opening to a degree ofthe aperture at the seat 33 to deliver the resultant pump pressure to the top of the piston 4 and a resulting downward pressure on the breech of the gun. ,l l

While a speciilc embodiment of the invention has been shown and been described, it will be understood that various alterationsmay be made without departure from the spirit of the invention as indicated by the appended claims.

- What I claim is: Y

1. In combination with a trunnion-mounted gun of the type having alternately operable manually-actuated mechanical means and automatically-controlled fluid pressure means for selectively positioning the gun about its trunnion axis, means engageable during operation lof thesaid mechanical means for modifying the said iiuid pressure means teA provide a positioning force biasing said gun in one direction only to take up backlash in said mechanical means.

2. In combination with a trunnion-mounted gun of the type having alternately operable manually-actuated mechanical means and automatically-controlled fluid pressure means for selectively positioning-the gun about its trunnion axis, means for modifying said fluid pressure means to provide a positioning force biasing said gun in one direction only to take up backlash in said mechanical means, and means for introducing the last named means during operation of said manually-actuated mechanical means.

3. In combination with a trunnion-mounted gun of the type having alternately operable manually-actuated mechanical means and automatically-controlled fluid pressure means for selectively positioning the gun about its trunnion axis, said automatically-controlled uid pressure means comprising piston means operatively connected to the a source of uid pressure, a gyro-controlled-circuit, and valve means responsive to said gym-controlled circuit for controlling the application of the iluid pressure to oppositelydirected areas of the piston means, means for actuating the valvemeans to apply fluid pressure to only one of the oppositely directed areas of the piston means and means for disconnecting said gym-controlled circuit during operation of said manually-actuated mechanical means.

4. In combination with a trunnion-mounted gun of the type having alternately operable manually-actuated mechanical means and automatically-controlled fluid pressure means for selectively positioning the gun about its trunnion axis, said automatically-controlled :duid pressure means comprising a cylinder, a piston mounted in said cylinder and adapted for connection to a trunnion-mounted gun, a member having a pair of passages connected respectively to said cylinder at opposite sides of said piston, a iiuid reservoir in communication with said passages, a. pump for transferring iiuid from said reservoir to said passages, a by-pass from each passage .to said reser- Voir, a magnetic teeter valve having a rocker with valve stems adapted to selectively obstruct said by-passes from the corresponding passages, a pair of coils acting on said valve, and a gyro-actuated circuit for selectively energizing said coils, a circuit external to the first circuit for energizing one of the coils to close the by-pass of the passage that exerts a downward force on said piston, and means for disconnecting said gyra-actuated circuit and for closing said external circuit when the gun is to be manually positioned.

5. In combination with an automatically-controlled fluid pressure means for selectively positioning a gun about its trunnion axis comprising uid pressure means for applying a, force on a gun in either direction about its trunnion axis, electrically actuated valve means for controlling the direction of the force on the gun, and a gyroactuated circuit for controlling said valve means, a circuit external to said gym-actuated circuit for actuating said valve to apply a force on the gun in one direction only, and means for disconnecting the gym-actuated circuit and closing the said external circuit whereby said fluid pressure means may be used to take up backlash when the gun is mechanically elevated.

6. In combination with an automatically-controlled fluid pressure means for selectively positioning a, gun about its trunnion axis comprising a cylinder, a piston mounted in said cylinder and adapted for connection to a trunnion-mounted gun, a member having a pair of passages connected respectively to said cylinder at opposite sides of said piston, a fluid reservoir in communication with said passages, a pump for transferring fluid from said reservoir to said passages, a bypass from each passage to said reservoir, a magnetic teeter valve having a rocker with valve stems adapted to' selectively obstruct said by-passes from the corresponding passages, a pair of coils acting on said valve, and a gyra-actuated circuit for selectively energizing said coils, a circuit external to the rst circuit for energizing one of the coils to close the by-pass of the passage that exerts a downward force on said piston, and means for disconnecting said gyro-actuated circuit and for closing said external circuit when the gun is to be manually positioned.

GEORGE I. CHINN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 339,466 Powlett l Apr, 6, 1886 1,493,628 Hagenbucher May 13. 19251 2,381,161 Lynn Aug. 7, 1945 

